kittydog42
New Member
I am trying to make a circuit that takes a 5V pulse in and provides a matching 12V pulse out. It doesn't matter if the output is inverted because it is changing state 3 times per second at a minimum. Both of the pulses have a common ground, and 12V power is available.
I used an NTE128 (NPN transistor). I wired the 5V pulse through a 1000 ohm resistor to the base. I wired the common ground to the collector. I wired a 1000 ohm pull-up resistor from the emitter to the 12V power source. The problem is, I am measuring only 8.5V on my oscilloscope at the emitter. It does pulse up and down to 0.7V as I was expecting, but I thought that the output would be 12V, not 8.5V. Another thing that I can't understand is that the voltage seems to rise when I increase the pull-up resistor value, which is the opposite of what I expected.
Are the any ideas as to why I am only seeing 8.5V at the emitter, when the pull-up is tied to 12V? Could it be my choice of transistor? Any help would be appreciated.
I used an NTE128 (NPN transistor). I wired the 5V pulse through a 1000 ohm resistor to the base. I wired the common ground to the collector. I wired a 1000 ohm pull-up resistor from the emitter to the 12V power source. The problem is, I am measuring only 8.5V on my oscilloscope at the emitter. It does pulse up and down to 0.7V as I was expecting, but I thought that the output would be 12V, not 8.5V. Another thing that I can't understand is that the voltage seems to rise when I increase the pull-up resistor value, which is the opposite of what I expected.
Are the any ideas as to why I am only seeing 8.5V at the emitter, when the pull-up is tied to 12V? Could it be my choice of transistor? Any help would be appreciated.